1
|
Verbeke J, Kamoen V, De Buyzere M, Claessens T, Timmermans F. The Pixel Variation Score: An Echocardiographic Index to Assess Temporal Variation of Mitral Regurgitant Flow. J Am Soc Echocardiogr 2024; 37:316-324. [PMID: 37913997 DOI: 10.1016/j.echo.2023.10.012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/12/2023] [Revised: 10/16/2023] [Accepted: 10/21/2023] [Indexed: 11/03/2023]
Abstract
BACKGROUND In mitral regurgitation (MR), temporal variation of MR flow has been considered an important reason for inaccurate MR grading. Current echocardiographic methods for assessing temporal MR flow variation are complex, and their clinical relevance has not been investigated. In this study, we investigated whether assessing MR flow variation using a dimensionless index with echocardiography is feasible, clinically meaningful, and related to patient outcomes. METHODS Consecutive patients with mitral valve prolapse (MVP, n = 244) and functional MR (FMR, n = 396) underwent comprehensive echocardiography. Mitral regurgitation severity was assessed using an integrated approach advocated by current guidelines. The MR continuous-wave Doppler envelope was divided into 3 segments of equal duration. Each segment's pixel intensity was assessed to calculate the pixel variation score (PVS). RESULTS The PVS was lower in FMR patients than in MVP patients. Lower PVS was associated with worse MR, larger left atrial and left ventricular dimensions, lower ejection fraction, and higher pulmonary artery pressures. In MVP, PVS was significantly associated with postoperative left ventricular reverse remodeling and was able to reclassify most patients in whom single-frame measures overestimated MR severity. Finally, PVS had incremental prognostic value on top of clinical and echocardiographic predictors of outcome. CONCLUSIONS Temporal variation in MR flow can reliably be assessed with echocardiography through analysis of the continuous-wave Doppler signal. A high PVS value may alert the echocardiographer to defer from single-frame MR grading and also suggests that the MR is probably not severe.
Collapse
Affiliation(s)
- Jonas Verbeke
- Department of Cardiology, University Hospital Ghent, Ghent University, Ghent, Belgium.
| | - Victor Kamoen
- Department of Cardiology, University Hospital Ghent, Ghent University, Ghent, Belgium
| | - Marc De Buyzere
- Department of Cardiology, University Hospital Ghent, Ghent University, Ghent, Belgium
| | - Tom Claessens
- Department of Materials, Textiles and Chemical Engineering, Ghent University, Ghent, Belgium
| | - Frank Timmermans
- Department of Cardiology, University Hospital Ghent, Ghent University, Ghent, Belgium
| |
Collapse
|
2
|
Wu X, Saaid H, Voorneveld J, Claessens T, Westenberg JJM, de Jong N, Bosch JG, Kenjereš S. 4D Flow Patterns and Relative Pressure Distribution in a Left Ventricle Model by Shake-the-Box and Proper Orthogonal Decomposition Analysis. Cardiovasc Eng Technol 2023; 14:743-754. [PMID: 37783950 PMCID: PMC10739257 DOI: 10.1007/s13239-023-00684-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/14/2022] [Accepted: 09/05/2023] [Indexed: 10/04/2023]
Abstract
PURPOSE Intraventricular blood flow dynamics are associated with cardiac function. Accurate, noninvasive, and easy assessments of hemodynamic quantities (such as velocity, vortex, and pressure) could be an important addition to the clinical diagnosis and treatment of heart diseases. However, the complex time-varying flow brings many challenges to the existing noninvasive image-based hemodynamic assessments. The development of reliable techniques and analysis tools is essential for the application of hemodynamic biomarkers in clinical practice. METHODS In this study, a time-resolved particle tracking method, Shake-the-Box, was applied to reconstruct the flow in a realistic left ventricle (LV) silicone model with biological valves. Based on the obtained velocity, 4D pressure field was calculated using a Poisson equation-based pressure solver. Furthermore, flow analysis by proper orthogonal decomposition (POD) of the 4D velocity field has been performed. RESULTS As a result of the Shake-the-Box algorithm, we have extracted: (i) particle positions, (ii) particle tracks, and finally, (iii) 4D velocity fields. From the latter, the temporal evolution of the 3D pressure field during the full cardiac cycle was obtained. The obtained maximal pressure difference extracted along the base-to-apex was about 2.7 mmHg, which is in good agreement with those reported in vivo. The POD analysis results showed a clear picture of different scale of vortices in the pulsatile LV flow, together with their time-varying information and corresponding kinetic energy content. To reconstruct 95% of the kinetic energy of the LV flow, only the first six POD modes would be required, leading to significant data reduction. CONCLUSIONS This work demonstrated Shake-the-Box is a promising technique to accurately reconstruct the left ventricle flow field in vitro. The good spatial and temporal resolutions of the velocity measurements enabled a 4D reconstruction of the pressure field in the left ventricle. The application of POD analysis showed its potential in reducing the complexity of the high-resolution left ventricle flow measurements. For future work, image analysis, multi-modality flow assessments, and the development of new flow-derived biomarkers can benefit from fast and data-reducing POD analysis.
Collapse
Affiliation(s)
- Xiaolin Wu
- Department of Chemical Engineering, Faculty of Applied Sciences, Delft University of Technology, Delft, The Netherlands.
- J. M. Burgerscentrum Research School for Fluid Mechanics, Delft, The Netherlands.
| | - Hicham Saaid
- Institute Biomedical Technology, Ghent University, Ghent, Belgium
| | - Jason Voorneveld
- Department of Biomedical Engineering, Thorax Center, Erasmus MC University Medical Center, Rotterdam, The Netherlands
| | - Tom Claessens
- Department of Materials, Textiles and Chemical Engineering, Ghent University, Ghent, Belgium
| | - Jos J M Westenberg
- CardioVascular Imaging Group, Department of Radiology, Leiden University Medical Center, Leiden, The Netherlands
| | - Nico de Jong
- Department of Biomedical Engineering, Thorax Center, Erasmus MC University Medical Center, Rotterdam, The Netherlands
| | - Johan G Bosch
- Department of Biomedical Engineering, Thorax Center, Erasmus MC University Medical Center, Rotterdam, The Netherlands
| | - Saša Kenjereš
- Department of Chemical Engineering, Faculty of Applied Sciences, Delft University of Technology, Delft, The Netherlands
- J. M. Burgerscentrum Research School for Fluid Mechanics, Delft, The Netherlands
| |
Collapse
|
3
|
Westenberg JJM, van Assen HC, van den Boogaard PJ, Goeman JJ, Saaid H, Voorneveld J, Bosch J, Kenjeres S, Claessens T, Garg P, Kouwenhoven M, Lamb HJ. Echo planar imaging-induced errors in intracardiac 4D flow MRI quantification. Magn Reson Med 2021; 87:2398-2411. [PMID: 34866236 PMCID: PMC9300143 DOI: 10.1002/mrm.29112] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2021] [Revised: 11/16/2021] [Accepted: 11/16/2021] [Indexed: 01/09/2023]
Abstract
Purpose To assess errors associated with EPI‐accelerated intracardiac 4D flow MRI (4DEPI) with EPI factor 5, compared with non‐EPI gradient echo (4DGRE). Methods Three 3T MRI experiments were performed comparing 4DEPI to 4DGRE: steady flow through straight tubes, pulsatile flow in a left‐ventricle phantom, and intracardiac flow in 10 healthy volunteers. For each experiment, 4DEPI was repeated with readout and blip phase‐encoding gradient in different orientations, parallel or perpendicular to the flow direction. In vitro flow rates were compared with timed volumetric collection. In the left‐ventricle phantom and in vivo, voxel‐based speed and spatio‐temporal median speed were compared between sequences, as well as mitral and aortic transvalvular net forward volume. Results In steady‐flow phantoms, the flow rate error was largest (12%) for high velocity (>2 m/s) with 4DEPI readout gradient parallel to the flow. Voxel‐based speed and median speed in the left‐ventricle phantom were ≤5.5% different between sequences. In vivo, mean net forward volume inconsistency was largest (6.4 ± 8.5%) for 4DEPI with nonblip phase‐encoding gradient parallel to the main flow. The difference in median speed for 4DEPI versus 4DGRE was largest (9%) when the 4DEPI readout gradient was parallel to the flow. Conclusions Velocity and flow rate are inaccurate for 4DEPI with EPI factor 5 when flow is parallel to the readout or blip phase‐encoding gradient. However, mean differences in flow rate, voxel‐based speed, and spatio‐temporal median speed were acceptable (≤10%) when comparing 4DEPI to 4DGRE for intracardiac flow in healthy volunteers.
Collapse
Affiliation(s)
- Jos J M Westenberg
- CardioVascular Imaging Group, Department of Radiology, Leiden University Medical Center, Leiden, the Netherlands
| | - Hans C van Assen
- CardioVascular Imaging Group, Department of Radiology, Leiden University Medical Center, Leiden, the Netherlands
| | - Pieter J van den Boogaard
- CardioVascular Imaging Group, Department of Radiology, Leiden University Medical Center, Leiden, the Netherlands
| | - Jelle J Goeman
- Department of Biomedical Data Sciences, Leiden University Medical Center, Leiden, the Netherlands
| | - Hicham Saaid
- Institute Biomedical Technology, Ghent University, Ghent, Belgium
| | - Jason Voorneveld
- Department of Biomedical Engineering, Erasmus Medical Center Rotterdam, Rotterdam, the Netherlands
| | - Johan Bosch
- Department of Biomedical Engineering, Erasmus Medical Center Rotterdam, Rotterdam, the Netherlands
| | - Sasa Kenjeres
- Department of Chemical Engineering, Delft University of Technology, Delft, the Netherlands
| | - Tom Claessens
- Department of Materials, Textiles and Chemical Engineering, Ghent University, Ghent, Belgium
| | - Pankaj Garg
- Department of Infection, Immunity and Cardiovascular Disease, University of Sheffield, Sheffield, UK
| | - Marc Kouwenhoven
- Department of MR R&D-Clinical Science, Philips, Best, the Netherlands
| | - Hildo J Lamb
- CardioVascular Imaging Group, Department of Radiology, Leiden University Medical Center, Leiden, the Netherlands
| |
Collapse
|
4
|
Voorneveld J, Saaid H, Schinkel C, Radeljic N, Lippe B, Gijsen FJH, van der Steen AFW, de Jong N, Claessens T, Vos HJ, Kenjeres S, Bosch JG. 4-D Echo-Particle Image Velocimetry in a Left Ventricular Phantom. Ultrasound Med Biol 2020; 46:805-817. [PMID: 31924419 DOI: 10.1016/j.ultrasmedbio.2019.11.020] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/15/2019] [Revised: 10/29/2019] [Accepted: 11/30/2019] [Indexed: 06/10/2023]
Abstract
Left ventricular (LV) blood flow is an inherently complex time-varying 3-D phenomenon, where 2-D quantification often ignores the effect of out-of-plane motion. In this study, we describe high frame rate 4-D echocardiographic particle image velocimetry (echo-PIV) using a prototype matrix transesophageal transducer and a dynamic LV phantom for testing the accuracy of echo-PIV in the presence of complex flow patterns. Optical time-resolved tomographic PIV (tomo-PIV) was used as a reference standard for comparison. Echo-PIV and tomo-PIV agreed on the general profile of the LV flow patterns, but echo-PIV smoothed out the smaller flow structures. Echo-PIV also underestimated the flow rates at greater imaging depths, where the PIV kernel size and transducer point spread function were large relative to the velocity gradients. We demonstrate that 4-D echo-PIV could be performed in just four heart cycles, which would require only a short breath-hold, providing promising results. However, methods for resolving high velocity gradients in regions of poor spatial resolution are required before clinical translation.
Collapse
Affiliation(s)
- Jason Voorneveld
- Department of Biomedical Engineering, Thorax Center, Erasmus MC University Medical Center, Rotterdam, the Netherlands.
| | - Hicham Saaid
- Institute Biomedical Technology, Ghent University, Ghent, Belgium
| | - Christiaan Schinkel
- Transport Phenomena Section, Department of Chemical Engineering, Faculty of Applied Sciences, Delft University of Technology; the Netherlands
| | | | | | - Frank J H Gijsen
- Department of Biomedical Engineering, Thorax Center, Erasmus MC University Medical Center, Rotterdam, the Netherlands
| | - Antonius F W van der Steen
- Department of Biomedical Engineering, Thorax Center, Erasmus MC University Medical Center, Rotterdam, the Netherlands; Laboratory of Acoustical Wavefield Imaging, Faculty of Applied Sciences, Delft University of Technology, Delft, the Netherlands
| | - Nico de Jong
- Department of Biomedical Engineering, Thorax Center, Erasmus MC University Medical Center, Rotterdam, the Netherlands; Laboratory of Acoustical Wavefield Imaging, Faculty of Applied Sciences, Delft University of Technology, Delft, the Netherlands
| | - Tom Claessens
- Department of Materials, Textiles and Chemical Engineering, Ghent University, Ghent, Belgium
| | - Hendrik J Vos
- Department of Biomedical Engineering, Thorax Center, Erasmus MC University Medical Center, Rotterdam, the Netherlands; Laboratory of Acoustical Wavefield Imaging, Faculty of Applied Sciences, Delft University of Technology, Delft, the Netherlands
| | - Sasa Kenjeres
- Transport Phenomena Section, Department of Chemical Engineering, Faculty of Applied Sciences, Delft University of Technology; the Netherlands
| | - Johan G Bosch
- Department of Biomedical Engineering, Thorax Center, Erasmus MC University Medical Center, Rotterdam, the Netherlands
| |
Collapse
|
5
|
Saaid H, Voorneveld J, Schinkel C, Westenberg J, Gijsen F, Segers P, Verdonck P, de Jong N, Bosch JG, Kenjeres S, Claessens T. Tomographic PIV in a model of the left ventricle: 3D flow past biological and mechanical heart valves. J Biomech 2019; 90:40-49. [DOI: 10.1016/j.jbiomech.2019.04.024] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2018] [Revised: 03/14/2019] [Accepted: 04/15/2019] [Indexed: 10/27/2022]
|
6
|
Van Tongel A, Claessens T, Verhofste B, De Wilde L. Reversed shoulder arthroplasty as treatment for late or ancient chronic glenohumeral dislocation. Acta Orthop Belg 2016; 82:637-642. [PMID: 29119907] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Chronic glenohumeral dislocation is a rare entity and several treatment options have been proposed. The aim of this study is to report the long-term follow-up of the reversed shoulder arthroplasty in patients with chronic glenohumeral dislocation. A retrospective analysis of all patients between January 2002 and December 2012 that were treated with a reversed shoulder arthroplasty for chronic anterior glenohumeral dislocations was performed. Pre-operative CT evaluation of the bone loss and fatty degeneration of the rotator cuff muscles was performed. Pre- and postoperative Constant-Murley score was evaluated. 6 patients (4 males and 2 females) with anterior glenohumeral dislocations were evaluated. Average age was 73 years (between 65-86 years). The average time of dislocation was 18 weeks (between 4 and 52 weeks). Average time of follow-up was 39 months (between 12 and 90 months). The CM improved from 33 (between 17 and 45) pre-op to 76 postop (between 55 and 89). No postoperative complications were observed. Reversed shoulder arthroplasty gives good results in case of chronic glenohumeral dislocation.
Collapse
|
7
|
Van Haver A, De Roo K, De Beule M, Labey L, De Baets P, Dejour D, Claessens T, Verdonk P. The effect of trochlear dysplasia on patellofemoral biomechanics: a cadaveric study with simulated trochlear deformities. Am J Sports Med 2015; 43:1354-61. [PMID: 25740833 DOI: 10.1177/0363546515572143] [Citation(s) in RCA: 109] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
BACKGROUND Trochlear dysplasia appears in different geometrical variations. The Dejour classification is widely used to grade the severity of trochlear dysplasia and to decide on treatment. PURPOSE To investigate the effect of trochlear dysplasia on patellofemoral biomechanics and to determine if different types of trochlear dysplasia have different effects on patellofemoral biomechanics. STUDY DESIGN Controlled laboratory study. METHODS Trochlear dysplasia was simulated in 4 cadaveric knees by replacing the native cadaveric trochlea with different types of custom-made trochlear implants, manufactured with 3-dimensional printing. For each knee, 5 trochlear implants were designed: 1 implant simulated the native trochlea (control condition), and 4 implants simulated 4 types of trochlear dysplasia. The knees were subjected to 3 biomechanical tests: a squat simulation, an open chain extension simulation, and a patellar stability test. The patellofemoral kinematics, contact area, contact pressure, and stability were compared between the control condition (replica implants) and the trochlear dysplastic condition and among the subgroups of trochlear dysplasia. RESULTS The patellofemoral joint in the trochlear dysplastic group showed increased internal rotation, lateral tilt, and lateral translation; increased contact pressures; decreased contact areas; and decreased stability when compared with the control group. Within the trochlear dysplastic group, the implants graded as Dejour type D showed the largest deviations for the kinematical parameters, and the implants graded as Dejour types B and D showed the largest deviations for the patellofemoral contact areas and pressures. CONCLUSION Patellofemoral kinematics, contact area, contact pressure, and stability are significantly affected by trochlear dysplasia. Of all types of trochlear dysplasia, the models characterized with a pronounced trochlear bump showed the largest deviations in patellofemoral biomechanics. CLINICAL RELEVANCE Investigating the relationship between the shape of the trochlea and patellofemoral biomechanics can provide insight into the short-term effects (maltracking, increased pressures, and instability) and long-term effects (osteoarthritis) of different types of trochlear dysplasia. Furthermore, this investigation provides an empirical explanation for better treatment outcomes of trochleoplasty for Dejour types B and D dysplasia.
Collapse
Affiliation(s)
- Annemieke Van Haver
- Department of Industrial Technology and Construction, Ghent University, Ghent, Belgium Department of Construction and Production, Ghent University, Ghent, Belgium Monica Orthopaedic Research (MORE) Institute, Antwerp, Belgium
| | - Karel De Roo
- Department of Physical medicine and orthopaedic surgery, Ghent University, Ghent, Belgium
| | - Matthieu De Beule
- Department of Civil Engineering, IBiTech-bioMMeda, Ghent University, Ghent, Belgium
| | - Luc Labey
- Department of Mechanical Engineering-Division of Biomechanics, Catholic University Leuven, Leuven, Belgium
| | - Patrick De Baets
- Department of Construction and Production, Ghent University, Ghent, Belgium
| | - David Dejour
- Department of Orthopaedics, Lyon-Ortho-Clinic, Clinique de la Sauvegarde, Lyon, France
| | - Tom Claessens
- Department of Industrial Technology and Construction, Ghent University, Ghent, Belgium
| | - Peter Verdonk
- Department of Physical medicine and orthopaedic surgery, Ghent University, Ghent, Belgium Antwerp Orthopedic Center, Monica Hospitals, Antwerp, Belgium
| |
Collapse
|
8
|
Van Haver A, De Roo K, De Beule M, Van Cauter S, Audenaert E, Claessens T, Verdonk P. Semi-automated landmark-based 3D analysis reveals new morphometric characteristics in the trochlear dysplastic femur. Knee Surg Sports Traumatol Arthrosc 2014; 22:2698-708. [PMID: 23778869 DOI: 10.1007/s00167-013-2573-1] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/22/2013] [Accepted: 06/10/2013] [Indexed: 01/12/2023]
Abstract
PURPOSE The authors hypothesise that the trochlear dysplastic distal femur is not only characterised by morphological changes to the trochlea. The purpose of this study is to describe the morphological characteristics of the trochlear dysplastic femur in and outside the trochlear region with a landmark-based 3D analysis. METHODS Arthro-CT scans of 20 trochlear dysplastic and 20 normal knees were used to generate 3D models including the cartilage. To rule out size differences, a set of landmarks were defined on the distal femur to isotropically scale the 3D models to a standard size. A predefined series of landmark-based reference planes were applied on the distal femur. With these landmarks and reference planes, a series of previously described characteristics associated with trochlear dysplasia as well as a series of morphometric characteristics were measured. RESULTS For the previously described characteristics, the analysis replicated highly significant differences between trochlear dysplastic and normal knees. Furthermore, the analysis showed that, when knee size is taken into account, the cut-off values of the trochlear bump and depth would be 1 mm larger in the largest knees compared to the smallest knees. For the morphometric characteristics, the analysis revealed that the trochlear dysplastic femur is also characterised by a 10% smaller intercondylar notch, 6-8% larger posterior condyles (lateral-medial) in the anteroposterior direction and a 6% larger medial condyle in the proximodistal direction compared to a normal femur. CONCLUSIONS This study shows that knee size is important in the application of absolute metric cut-off values and that the posterior femur also shows a significantly different morphology.
Collapse
Affiliation(s)
- Annemieke Van Haver
- BioMech, Department of Mechanics, University College Ghent, Valentin Vaerwijckweg 1, 9000, Ghent, Belgium,
| | | | | | | | | | | | | |
Collapse
|
9
|
Van Haver A, De Roo K, De Beule M, Van Cauter S, Labey L, De Baets P, Claessens T, Verdonk P. The use of rapid prototyped implants to simulate knee joint abnormalities for in vitro testing: A validation study with replica implants of the native trochlea. Proc Inst Mech Eng H 2014; 228:833-42. [DOI: 10.1177/0954411914548242] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
To investigate the biomechanical effect of skeletal knee joint abnormalities, the authors propose to implant pathologically shaped rapid prototyped implants in cadaver knee specimens. This new method was validated by replacing the native trochlea by a replica implant on four cadaver knees with the aid of cadaver-specific guiding instruments. The accuracy of the guiding instruments was assessed by measuring the rotational errors of the cutting planes (on average 3.01° in extension and 1.18° in external/internal rotation). During a squat and open chain simulation, the patella showed small differences in its articulation with the native trochlea and the replica trochlea, which could partially be explained by the rotational errors of the implants. This study concludes that this method is valid to investigate the effect of knee joint abnormalities with a replica implant as a control condition to account for the influence of material properties and rotational errors of the implant.
Collapse
Affiliation(s)
- Annemieke Van Haver
- Department of Industrial Technology and Construction, Ghent University, Ghent, Belgium
- Department of Construction and Production, Ghent University, Ghent, Belgium
- Monica Orthopaedic Research Institute (MORE Institute), Antwerp, Belgium
| | - Karel De Roo
- Department of Physical Medicine and Orthopaedic Surgery, Ghent University, Ghent, Belgium
- Department of Orthopedics and Traumatology, University Hospital Ghent, Ghent, Belgium
| | - Matthieu De Beule
- IBiTech – bioMMeda, Department of Electronics and Information Systems, iMinds Future Health Department, Ghent University, Ghent, Belgium
| | - Sofie Van Cauter
- IBiTech – bioMMeda, Department of Electronics and Information Systems, iMinds Future Health Department, Ghent University, Ghent, Belgium
| | - Luc Labey
- European Centre for Knee Research, Smith & Nephew, Inc., Leuven, Belgium
| | - Patrick De Baets
- Department of Construction and Production, Ghent University, Ghent, Belgium
| | - Tom Claessens
- Department of Industrial Technology and Construction, Ghent University, Ghent, Belgium
- IBiTech – bioMMeda, Department of Electronics and Information Systems, iMinds Future Health Department, Ghent University, Ghent, Belgium
| | - Peter Verdonk
- Monica Orthopaedic Research Institute (MORE Institute), Antwerp, Belgium
- Department of Physical Medicine and Orthopaedic Surgery, Ghent University, Ghent, Belgium
- Monica Hospital, Antwerp, Belgium
| |
Collapse
|
10
|
Annerel S, Claessens T, Taelman L, Degroote J, Van Nooten G, Verdonck P, Segers P, Vierendeels J. Influence of valve size, orientation and downstream geometry of an aortic BMHV on leaflet motion and clinically used valve performance parameters. Ann Biomed Eng 2014; 43:1370-84. [PMID: 25186435 DOI: 10.1007/s10439-014-1102-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2014] [Accepted: 08/25/2014] [Indexed: 11/30/2022]
Abstract
The aim of this study was to reconcile some of our own previous work and the work of others to generate a physiologically realistic numerical simulation environment that allows to virtually assess the performance of BMHVs. The model incorporates: (i) a left ventricular deformable model to generate a physiological inflow to the aortic valve; (ii) a patient-specific aortic geometry (root, arch and descending aorta); (iii) physiological pressure and flow boundary conditions. We particularly studied the influence of downstream geometry, valve size and orientation on leaflet kinematics and functional indices used in clinical routine. Compared to the straight tube geometry, the patient-specific aorta leads to a significant asynchronous movement of the valve, especially during the closing of the valve. The anterior leaflet starts to close first, impacts the casing at the closed position and remains in this position. At the same time, the posterior leaflet impacts the pivoting mechanisms at the fully open position. At the end of systole, this leaflet subsequently accelerates to the closed position, impacting the casing with an angular velocity of approximately -477 rad/s. The valve size greatly influences the transvalvular pressure gradient (TPG), but does not change the overall leaflet kinematics. This is in contrast to changes in valve orientation, where changing valve orientation induces large differences in leaflet kinematics, but the TPG remains approximately the same.
Collapse
Affiliation(s)
- S Annerel
- Department of Flow, Heat and Combustion Mechanics, Ghent University, Sint-Pietersnieuwstraat 41, 9000, Ghent, Belgium,
| | | | | | | | | | | | | | | |
Collapse
|
11
|
Chirinos JA, Rietzschel ER, Shiva-Kumar P, De Buyzere ML, Zamani P, Claessens T, Geraci S, Konda P, De Bacquer D, Akers SR, Gillebert TC, Segers P. Effective arterial elastance is insensitive to pulsatile arterial load. Hypertension 2014; 64:1022-31. [PMID: 25069668 DOI: 10.1161/hypertensionaha.114.03696] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Effective arterial elastance (E(A)) was proposed as a lumped parameter that incorporates pulsatile and resistive afterload and is increasingly being used in clinical studies. Theoretical modeling studies suggest that E(A) is minimally affected by pulsatile load, but little human data are available. We assessed the relationship between E(A) and arterial load determined noninvasively from central pressure-flow analyses among middle-aged adults in the general population (n=2367) and a diverse clinical population of older adults (n=193). In a separate study, we investigated the sensitivity of E(A) to changes in pulsatile load induced by isometric exercise (n=73). The combination of systemic vascular resistance and heart rate predicted 95.6% and 97.8% of the variability in E(A) among middle-aged and older adults, respectively. E(A) demonstrated a quasi-perfect linear relationship with the ratio of systemic vascular resistance/heart period (middle-aged adults, R=0.972; older adults, R=0.99; P<0.0001). Aortic characteristic impedance, total arterial compliance, reflection magnitude, and timing accounted together for <1% of the variability in E(A) in either middle-aged or older adults. Despite pronounced changes in pulsatile load induced by isometric exercise, changes in E(A) were not independently associated with changes pulsatile load but were rather a nearly perfect linear function of the ratio of systemic vascular resistance/heart period (R=0.99; P<0.0001). Our findings demonstrate that E(A) is simply a function of systemic vascular resistance and heart rate and is negligibly influenced by (and insensitive to) changes in pulsatile afterload in humans. Its current interpretation as a lumped parameter of pulsatile and resistive afterload should thus be reassessed.
Collapse
Affiliation(s)
- Julio A Chirinos
- From the Department of Medicine, Perelman School of Medicine and Hospital of the University of Pennsylvania, Philadelphia (J.A.C., P.Z.); Department of Medicine, Philadelphia VA Medical Center, PA (J.A.C., P.S.-K., S.R.A., S.G.); Department of Cardiovascular Diseases, Ghent University Hospital, Ghent, Belgium (E.R.R., M.L.D.B., D.D.B.); and Department of Public Health (E.R.R.), Department of Industrial Technology and Construction (T.C.), and Institute Biomedical Technology, iMinds Future Health Department (T.C., P.S.), Ghent University, Ghent, Belgium.
| | - Ernst R Rietzschel
- From the Department of Medicine, Perelman School of Medicine and Hospital of the University of Pennsylvania, Philadelphia (J.A.C., P.Z.); Department of Medicine, Philadelphia VA Medical Center, PA (J.A.C., P.S.-K., S.R.A., S.G.); Department of Cardiovascular Diseases, Ghent University Hospital, Ghent, Belgium (E.R.R., M.L.D.B., D.D.B.); and Department of Public Health (E.R.R.), Department of Industrial Technology and Construction (T.C.), and Institute Biomedical Technology, iMinds Future Health Department (T.C., P.S.), Ghent University, Ghent, Belgium
| | - Prithvi Shiva-Kumar
- From the Department of Medicine, Perelman School of Medicine and Hospital of the University of Pennsylvania, Philadelphia (J.A.C., P.Z.); Department of Medicine, Philadelphia VA Medical Center, PA (J.A.C., P.S.-K., S.R.A., S.G.); Department of Cardiovascular Diseases, Ghent University Hospital, Ghent, Belgium (E.R.R., M.L.D.B., D.D.B.); and Department of Public Health (E.R.R.), Department of Industrial Technology and Construction (T.C.), and Institute Biomedical Technology, iMinds Future Health Department (T.C., P.S.), Ghent University, Ghent, Belgium
| | - Marc L De Buyzere
- From the Department of Medicine, Perelman School of Medicine and Hospital of the University of Pennsylvania, Philadelphia (J.A.C., P.Z.); Department of Medicine, Philadelphia VA Medical Center, PA (J.A.C., P.S.-K., S.R.A., S.G.); Department of Cardiovascular Diseases, Ghent University Hospital, Ghent, Belgium (E.R.R., M.L.D.B., D.D.B.); and Department of Public Health (E.R.R.), Department of Industrial Technology and Construction (T.C.), and Institute Biomedical Technology, iMinds Future Health Department (T.C., P.S.), Ghent University, Ghent, Belgium
| | - Payman Zamani
- From the Department of Medicine, Perelman School of Medicine and Hospital of the University of Pennsylvania, Philadelphia (J.A.C., P.Z.); Department of Medicine, Philadelphia VA Medical Center, PA (J.A.C., P.S.-K., S.R.A., S.G.); Department of Cardiovascular Diseases, Ghent University Hospital, Ghent, Belgium (E.R.R., M.L.D.B., D.D.B.); and Department of Public Health (E.R.R.), Department of Industrial Technology and Construction (T.C.), and Institute Biomedical Technology, iMinds Future Health Department (T.C., P.S.), Ghent University, Ghent, Belgium
| | - Tom Claessens
- From the Department of Medicine, Perelman School of Medicine and Hospital of the University of Pennsylvania, Philadelphia (J.A.C., P.Z.); Department of Medicine, Philadelphia VA Medical Center, PA (J.A.C., P.S.-K., S.R.A., S.G.); Department of Cardiovascular Diseases, Ghent University Hospital, Ghent, Belgium (E.R.R., M.L.D.B., D.D.B.); and Department of Public Health (E.R.R.), Department of Industrial Technology and Construction (T.C.), and Institute Biomedical Technology, iMinds Future Health Department (T.C., P.S.), Ghent University, Ghent, Belgium
| | - Salvatore Geraci
- From the Department of Medicine, Perelman School of Medicine and Hospital of the University of Pennsylvania, Philadelphia (J.A.C., P.Z.); Department of Medicine, Philadelphia VA Medical Center, PA (J.A.C., P.S.-K., S.R.A., S.G.); Department of Cardiovascular Diseases, Ghent University Hospital, Ghent, Belgium (E.R.R., M.L.D.B., D.D.B.); and Department of Public Health (E.R.R.), Department of Industrial Technology and Construction (T.C.), and Institute Biomedical Technology, iMinds Future Health Department (T.C., P.S.), Ghent University, Ghent, Belgium
| | - Prasad Konda
- From the Department of Medicine, Perelman School of Medicine and Hospital of the University of Pennsylvania, Philadelphia (J.A.C., P.Z.); Department of Medicine, Philadelphia VA Medical Center, PA (J.A.C., P.S.-K., S.R.A., S.G.); Department of Cardiovascular Diseases, Ghent University Hospital, Ghent, Belgium (E.R.R., M.L.D.B., D.D.B.); and Department of Public Health (E.R.R.), Department of Industrial Technology and Construction (T.C.), and Institute Biomedical Technology, iMinds Future Health Department (T.C., P.S.), Ghent University, Ghent, Belgium
| | - Dirk De Bacquer
- From the Department of Medicine, Perelman School of Medicine and Hospital of the University of Pennsylvania, Philadelphia (J.A.C., P.Z.); Department of Medicine, Philadelphia VA Medical Center, PA (J.A.C., P.S.-K., S.R.A., S.G.); Department of Cardiovascular Diseases, Ghent University Hospital, Ghent, Belgium (E.R.R., M.L.D.B., D.D.B.); and Department of Public Health (E.R.R.), Department of Industrial Technology and Construction (T.C.), and Institute Biomedical Technology, iMinds Future Health Department (T.C., P.S.), Ghent University, Ghent, Belgium
| | - Scott R Akers
- From the Department of Medicine, Perelman School of Medicine and Hospital of the University of Pennsylvania, Philadelphia (J.A.C., P.Z.); Department of Medicine, Philadelphia VA Medical Center, PA (J.A.C., P.S.-K., S.R.A., S.G.); Department of Cardiovascular Diseases, Ghent University Hospital, Ghent, Belgium (E.R.R., M.L.D.B., D.D.B.); and Department of Public Health (E.R.R.), Department of Industrial Technology and Construction (T.C.), and Institute Biomedical Technology, iMinds Future Health Department (T.C., P.S.), Ghent University, Ghent, Belgium
| | - Thierry C Gillebert
- From the Department of Medicine, Perelman School of Medicine and Hospital of the University of Pennsylvania, Philadelphia (J.A.C., P.Z.); Department of Medicine, Philadelphia VA Medical Center, PA (J.A.C., P.S.-K., S.R.A., S.G.); Department of Cardiovascular Diseases, Ghent University Hospital, Ghent, Belgium (E.R.R., M.L.D.B., D.D.B.); and Department of Public Health (E.R.R.), Department of Industrial Technology and Construction (T.C.), and Institute Biomedical Technology, iMinds Future Health Department (T.C., P.S.), Ghent University, Ghent, Belgium
| | - Patrick Segers
- From the Department of Medicine, Perelman School of Medicine and Hospital of the University of Pennsylvania, Philadelphia (J.A.C., P.Z.); Department of Medicine, Philadelphia VA Medical Center, PA (J.A.C., P.S.-K., S.R.A., S.G.); Department of Cardiovascular Diseases, Ghent University Hospital, Ghent, Belgium (E.R.R., M.L.D.B., D.D.B.); and Department of Public Health (E.R.R.), Department of Industrial Technology and Construction (T.C.), and Institute Biomedical Technology, iMinds Future Health Department (T.C., P.S.), Ghent University, Ghent, Belgium
| |
Collapse
|
12
|
Annerel S, Claessens T, Degroote J, Segers P, Vierendeels J. Validation of a numerical FSI simulation of an aortic BMHV by in vitro PIV experiments. Med Eng Phys 2014; 36:1014-23. [PMID: 24924383 DOI: 10.1016/j.medengphy.2014.05.004] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2013] [Revised: 04/01/2014] [Accepted: 05/05/2014] [Indexed: 10/25/2022]
Abstract
In this paper, a validation of a recently developed fluid-structure interaction (FSI) coupling algorithm to simulate numerically the dynamics of an aortic bileaflet mechanical heart valve (BMHV) is performed. This validation is done by comparing the numerical simulation results with in vitro experiments. For the in vitro experiments, the leaflet kinematics and flow fields are obtained via the particle image velocimetry (PIV) technique. Subsequently, the same case is numerically simulated by the coupling algorithm and the resulting leaflet kinematics and flow fields are obtained. Finally, the results are compared, revealing great similarity in leaflet motion and flow fields between the numerical simulation and the experimental test. Therefore, it is concluded that the developed algorithm is able to capture very accurately all the major leaflet kinematics and dynamics and can be used to study and optimize the design of BMHVs.
Collapse
Affiliation(s)
- S Annerel
- Ghent University, Department of Flow, Heat and Combustion Mechanics, Sint-Pietersnieuwstraat 41, B-9000 Ghent, Belgium.
| | - T Claessens
- Ghent University, Department of Industrial Technology and Construction, Valentin Vaerwyckweg 1, B-9000 Ghent, Belgium.
| | - J Degroote
- Ghent University, Department of Flow, Heat and Combustion Mechanics, Sint-Pietersnieuwstraat 41, B-9000 Ghent, Belgium.
| | - P Segers
- Ghent University, iMinds Medical IT, IBiTech-bioMMeda, De Pintelaan 185, B-9000 Ghent, Belgium.
| | - J Vierendeels
- Ghent University, Department of Flow, Heat and Combustion Mechanics, Sint-Pietersnieuwstraat 41, B-9000 Ghent, Belgium.
| |
Collapse
|
13
|
Van Haver A, Mahieu P, Claessens T, Li H, Pattyn C, Verdonk P, Audenaert EA. A statistical shape model of trochlear dysplasia of the knee. Knee 2014; 21:518-23. [PMID: 24359641 DOI: 10.1016/j.knee.2013.11.016] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/22/2013] [Revised: 10/11/2013] [Accepted: 11/22/2013] [Indexed: 02/02/2023]
Abstract
BACKGROUND Trochlear dysplasia is known as the primary predisposing factor for patellar dislocation. Current methods to describe trochlear dysplasia are mainly qualitative or based on a limited number of discrete measurements. The purpose of this study is to apply statistical shape analysis to take the full geometrical complexity of trochlear dysplasia into account. METHODS Statistical shape analysis was applied to 20 normal and 20 trochlear dysplastic distal femur models, including the cartilage. RESULTS This study showed that the trochlea was anteriorized, proximalized and lateralized and that the mediolateral width and the notch width were decreased in the trochlear dysplastic femur compared to the normal femur. The first three principal components of the trochlear dysplastic femurs, accounting for 79.7% of the total variation, were size, sulcus angle and notch width. Automated classification of the trochlear dysplastic and normal femora achieved a sensitivity of 85% and a specificity of 95%. CONCLUSIONS This study shows that shape analysis is an outstanding method to visualise the location and magnitude of shape abnormalities. Improvement of automated classification and subtyping within the trochlear dysplastic group are expected when larger training sets are used. CLINICAL RELEVANCE Classification of trochlear dysplasia, especially borderline cases may be facilitated by automated classification. Furthermore, the identification of a decreased notch width in association with an increased sulcus angle can also contribute to the diagnosis of trochlear dysplasia.
Collapse
Affiliation(s)
- A Van Haver
- Department of Mechanics, BioMech, University College Ghent, Valentin Vaerwijckweg 1, 9000 Ghent, Belgium; Department of Production and Construction, Ghent University, 9052 Zwijnaarde, Belgium; Monica Orthopaedic Research Institute (MORE Institute), 2100 Antwerp, Belgium.
| | - P Mahieu
- Department of Physical medicine and Orthopaedic Surgery, Ghent University, De Pintelaan 185, 9000 Ghent, Belgium
| | - T Claessens
- Department of Mechanics, BioMech, University College Ghent, Valentin Vaerwijckweg 1, 9000 Ghent, Belgium; Department of Civil Engineering, IBiTech - bioMMeda, Ghent University, De Pintelaan 185, 9000 Ghent, Belgium
| | - H Li
- Department of Computer Science, University of Southern California, USA
| | - C Pattyn
- Department of Physical medicine and Orthopaedic Surgery, Ghent University, De Pintelaan 185, 9000 Ghent, Belgium
| | - P Verdonk
- Department of Physical medicine and Orthopaedic Surgery, Ghent University, De Pintelaan 185, 9000 Ghent, Belgium; Monica Hospital, 2100 Antwerp, Belgium
| | - E A Audenaert
- Department of Physical medicine and Orthopaedic Surgery, Ghent University, De Pintelaan 185, 9000 Ghent, Belgium
| |
Collapse
|
14
|
Botti L, Van Canneyt K, Kaminsky R, Claessens T, Planken RN, Verdonck P, Remuzzi A, Antiga L. Numerical Evaluation and Experimental Validation of Pressure Drops Across a Patient-Specific Model of Vascular Access for Hemodialysis. Cardiovasc Eng Technol 2013. [DOI: 10.1007/s13239-013-0162-6] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
|
15
|
Van Haver A, De Roo K, Claessens T, De Beule M, Verdonk P, De Baets P. Pilot validation study on a quasi-static weight-bearing knee rig. Proc Inst Mech Eng H 2013; 227:229-33. [PMID: 23662338 DOI: 10.1177/0954411912472595] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
This article presents a pilot study on a quasi-static knee rig designed to investigate the influence of pathologies and surgical interventions on the patellofemoral kinetics of cadaveric knees. The knee rig allows cadaveric knees to flex and extend under a simulated body weight by transmitting a force to the quadriceps tendon. During the squat simulation, the ground reaction force stays within physiological values. Before using this device to answer clinical questions, two knee specimens were tested to assess the repeatability of the rig. Four repeated flexion-extension cycles were performed under a simulated body weight of 700 N, with an isolated force on the quadriceps tendon up to 2700 N and with a ground reaction force close to 350 N. The resulting patellofemoral contact area shifted from distal to proximal during knee flexion. From 20 degrees to 60 degrees of knee flexion, the mean contact area and pressure increased from 80.2 +/- 3.3 to 349.5 +/- 10.1 mm2 and from 0.9 +/- 0.2 to 5.9 +/- 0.7 MPa, respectively. The transmitted force on the quadriceps tendon, the ground reaction force and the patellofemoral contact area and pressure were continuously measured and showed a relative variability of 1.6%, 2.4%, 2.8% and 3.2%, respectively. The presented knee rig shows a good repeatability that allows us to use this knee rig to quantify the influence of anatomical changes on the patellofemoral contact area and pressures during a squat simulation.
Collapse
Affiliation(s)
- Annemieke Van Haver
- Department of Mechanical Engineering, BioMech, University College Ghent, Ghent, Belgium.
| | | | | | | | | | | |
Collapse
|
16
|
Van Der Smissen B, Claessens T, Verdonck P, Van Ransbeeck P, Segers P. Modelling the left ventricle using rapid prototyping techniques. Ing Rech Biomed 2013. [DOI: 10.1016/j.irbm.2013.04.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
|
17
|
Chirinos JA, Rietzschel ER, De Buyzere ML, Claessens T, De Bacquer D, Gillebert TC, Segers P. RELATIONSHIP BETWEEN EFFECTS ARTERIAL ELASTANCE AND SPECIFIC MEASURES OF ARTERIAL PROPERTIES IN MIDDLE AGE: THE ASKLEPIOS STUDY. J Am Coll Cardiol 2013. [DOI: 10.1016/s0735-1097(13)61444-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
|
18
|
Chirinos JA, Segers P, Rietzschel ER, De Buyzere ML, Raja MW, Claessens T, De Bacquer D, St. John Sutton M, Gillebert TC. Early and Late Systolic Wall Stress Differentially Relate to Myocardial Contraction and Relaxation in Middle-Aged Adults. Hypertension 2013; 61:296-303. [DOI: 10.1161/hypertensionaha.111.00530] [Citation(s) in RCA: 94] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Affiliation(s)
- Julio A. Chirinos
- From the Philadelphia VA Medical Center and University of Pennsylvania, Philadelphia, PA (J.A.C., M.W.R., M.S.J.S.); Institute Biomedical Technology (P.S., T.C.) and Department of Public Health (E.R.R., D.D.B.), Ghent University, Ghent, Belgium; Department of Cardiovascular Diseases, Ghent University Hospital, Ghent, Belgium (E.R.R., M.L.D.B., T.C.G.); and Department of Mechanics, University College Ghent, Ghent, Belgium (T.C.)
| | - Patrick Segers
- From the Philadelphia VA Medical Center and University of Pennsylvania, Philadelphia, PA (J.A.C., M.W.R., M.S.J.S.); Institute Biomedical Technology (P.S., T.C.) and Department of Public Health (E.R.R., D.D.B.), Ghent University, Ghent, Belgium; Department of Cardiovascular Diseases, Ghent University Hospital, Ghent, Belgium (E.R.R., M.L.D.B., T.C.G.); and Department of Mechanics, University College Ghent, Ghent, Belgium (T.C.)
| | - Ernst R. Rietzschel
- From the Philadelphia VA Medical Center and University of Pennsylvania, Philadelphia, PA (J.A.C., M.W.R., M.S.J.S.); Institute Biomedical Technology (P.S., T.C.) and Department of Public Health (E.R.R., D.D.B.), Ghent University, Ghent, Belgium; Department of Cardiovascular Diseases, Ghent University Hospital, Ghent, Belgium (E.R.R., M.L.D.B., T.C.G.); and Department of Mechanics, University College Ghent, Ghent, Belgium (T.C.)
| | - Marc L. De Buyzere
- From the Philadelphia VA Medical Center and University of Pennsylvania, Philadelphia, PA (J.A.C., M.W.R., M.S.J.S.); Institute Biomedical Technology (P.S., T.C.) and Department of Public Health (E.R.R., D.D.B.), Ghent University, Ghent, Belgium; Department of Cardiovascular Diseases, Ghent University Hospital, Ghent, Belgium (E.R.R., M.L.D.B., T.C.G.); and Department of Mechanics, University College Ghent, Ghent, Belgium (T.C.)
| | - Muhammad W. Raja
- From the Philadelphia VA Medical Center and University of Pennsylvania, Philadelphia, PA (J.A.C., M.W.R., M.S.J.S.); Institute Biomedical Technology (P.S., T.C.) and Department of Public Health (E.R.R., D.D.B.), Ghent University, Ghent, Belgium; Department of Cardiovascular Diseases, Ghent University Hospital, Ghent, Belgium (E.R.R., M.L.D.B., T.C.G.); and Department of Mechanics, University College Ghent, Ghent, Belgium (T.C.)
| | - Tom Claessens
- From the Philadelphia VA Medical Center and University of Pennsylvania, Philadelphia, PA (J.A.C., M.W.R., M.S.J.S.); Institute Biomedical Technology (P.S., T.C.) and Department of Public Health (E.R.R., D.D.B.), Ghent University, Ghent, Belgium; Department of Cardiovascular Diseases, Ghent University Hospital, Ghent, Belgium (E.R.R., M.L.D.B., T.C.G.); and Department of Mechanics, University College Ghent, Ghent, Belgium (T.C.)
| | - Dirk De Bacquer
- From the Philadelphia VA Medical Center and University of Pennsylvania, Philadelphia, PA (J.A.C., M.W.R., M.S.J.S.); Institute Biomedical Technology (P.S., T.C.) and Department of Public Health (E.R.R., D.D.B.), Ghent University, Ghent, Belgium; Department of Cardiovascular Diseases, Ghent University Hospital, Ghent, Belgium (E.R.R., M.L.D.B., T.C.G.); and Department of Mechanics, University College Ghent, Ghent, Belgium (T.C.)
| | - Martin St. John Sutton
- From the Philadelphia VA Medical Center and University of Pennsylvania, Philadelphia, PA (J.A.C., M.W.R., M.S.J.S.); Institute Biomedical Technology (P.S., T.C.) and Department of Public Health (E.R.R., D.D.B.), Ghent University, Ghent, Belgium; Department of Cardiovascular Diseases, Ghent University Hospital, Ghent, Belgium (E.R.R., M.L.D.B., T.C.G.); and Department of Mechanics, University College Ghent, Ghent, Belgium (T.C.)
| | - Thierry C. Gillebert
- From the Philadelphia VA Medical Center and University of Pennsylvania, Philadelphia, PA (J.A.C., M.W.R., M.S.J.S.); Institute Biomedical Technology (P.S., T.C.) and Department of Public Health (E.R.R., D.D.B.), Ghent University, Ghent, Belgium; Department of Cardiovascular Diseases, Ghent University Hospital, Ghent, Belgium (E.R.R., M.L.D.B., T.C.G.); and Department of Mechanics, University College Ghent, Ghent, Belgium (T.C.)
| |
Collapse
|
19
|
Annerel S, Degroote J, Claessens T, Dahl SK, Skallerud B, Hellevik LR, Van Ransbeeck P, Segers P, Verdonck P, Vierendeels J. A fast strong coupling algorithm for the partitioned fluid–structure interaction simulation of BMHVs. Comput Methods Biomech Biomed Engin 2012; 15:1281-312. [DOI: 10.1080/10255842.2011.586946] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
|
20
|
Vanhercke D, Claessens T, Pardaens S, Ransbeeck PV, Vandekerckhove H, Verdonck P, Sutter JD. Assessment of variables affecting late left ventricular flow propagation velocity. Acta Cardiol 2012; 67:391-7. [PMID: 22997992 DOI: 10.1080/ac.67.4.2170679] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
UNLABELLED Early colour M-mode flow propagation velocity (Vpe) in the left ventricle is a well-known non-invasive index for assessing left ventricular relaxation. However, the utility and determinants of late colour M-mode flow propagation (Vpa) have received little attention to date. Vpa as a representation of the left ventricular vortex travelling velocity during late filling could have a distinct role in differentiating potential subgroups in diastolic failure. The aim of the present study was to establish the normal values of late flow propagation in a healthy population of various ages (18-79 years), and to examine the general and echocardiographic variables that affect Vpa. METHODS We studied 75 apparently healthy subjects (age range, 18-79 years; 38 women, 37 men) as part of an outpatient clinic check-up screening. General parameters were recorded, including age, gender, height, weight, blood pressure, and heart rate. In addition, conventional grey-scale M-mode, 2D, as well as colour M-mode, 2D, and pulsed wave (tissue) Doppler echocardiographic parameters were obtained in a single centre and using a single operator setting. Backward linear regression analysis (dependent variable: Vpa) was performed to find the optimal model, taking into account multicollinearity and maximum coefficient of determination (R2). Due to the heteroscedasticity of the collected data, a logarithmic transformation was used. In addition, separate linear backward regression analysis was performed for the male and female subgroups. RESULTS Vpa values were 26-179 cm/s. The optimal regression model after elimination included the following variables: age (beta = 0.684, P < 0.001), height (beta = 0.521, P < 0.001), gender (beta = 0.343, P < 0.05), left ventricular Vpe (beta = 0.299, P < 0.01), left ventricular posterior systolic (M-mode) wall thickness (beta = 0.288, P < 0.01), interventricular septum thickness diastole (beta = 0.346, P < 0.005), transmitral Doppler E-wave deceleration time apical 4-chamber (beta = -0.297, P < 0.05), and tissue Doppler peak E-wave mitral annulus (beta = 0.459, P < 0.005). The total coefficient of determination (R2) for this model was 0.540 (P < 0.001); 0.673 (P < 0.001) for men and 0.645 (P < 0.001) for women. CONCLUSION Vpa, representing left ventricular vortex travelling velocity during late filling, shows a large range of values in normal healthy subjects. It is mainly depending on age, gender and left ventricular mass. Moreover, substantially different determinants are found between men and women. Further study is required to explore these findings.
Collapse
Affiliation(s)
- Daniel Vanhercke
- AZ St-Lucas Hospital, Ghent, Belgium
- Ghent University, Institute Biomedical Technology, Ghent, Belgium
| | | | | | | | | | - Pascal Verdonck
- Ghent University, Institute Biomedical Technology, Ghent, Belgium
| | | |
Collapse
|
21
|
Maes F, Claessens T, Moesen M, Van Oosterwyck H, Van Ransbeeck P, Verdonck P. Computational models for wall shear stress estimation in scaffolds: A comparative study of two complete geometries. J Biomech 2012; 45:1586-92. [DOI: 10.1016/j.jbiomech.2012.04.015] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2011] [Revised: 03/19/2012] [Accepted: 04/09/2012] [Indexed: 12/24/2022]
|
22
|
Annerel S, Degroote J, Claessens T, Segers P, Verdonck P, Vierendeels J. The upstream boundary condition influences the leaflet opening dynamics in the numerical FSI simulation of an aortic BMHV. Int J Numer Method Biomed Eng 2012; 28:745-760. [PMID: 25364849 DOI: 10.1002/cnm.2470] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/30/2011] [Revised: 01/04/2012] [Accepted: 01/06/2012] [Indexed: 06/04/2023]
Abstract
In this paper, the influence of the upstream boundary condition in the numerical simulation of an aortic bileaflet mechanical heart valve (BMHV) is studied. Three three-dimensional cases with different upstream boundary conditions are compared. The first case consists of a rigid straight tube with a velocity profile at its inlet. In the second case, the upstream geometry is a contracting left ventricle (LV), positioned symmetrically with respect to the valve. In the last case, the LV is positioned asymmetrical with respect to the valve. The cases are used to simulate the same three-dimensional BMHV. The change in time of the LV volume is calculated such that the flow rate through the valve is identical in each case. The opening dynamics of the BMHV are modelled using fluid-structure interaction. The simulations show that differences occur in the leaflet movement of the three cases. In particular, with the asymmetric LV, one of the leaflets impacts the blocking mechanism at its open position with a 34% higher velocity than when using the velocity profile, and with an 88% higher velocity than in the symmetric LV case. Therefore, when simulating such an impact, the upstream boundary condition needs to be chosen carefully.
Collapse
Affiliation(s)
- Sebastiaan Annerel
- Department of Flow, Heat and Combustion Mechanics, Ghent University, Sint-Pietersnieuwstraat 41, B-9000, Ghent, Belgium.
| | | | | | | | | | | |
Collapse
|
23
|
Vanhercke D, Claessens T, Van Ransbeeck P, Vandekerckhove H, De Bisschop F, Segers P, Verdonck P. P169 Assessment of variables affecting late left ventricular flow propagation velocity (Vpa): an echocardiographic study. Eur J Cardiovasc Nurs 2011. [DOI: 10.1016/s1474-5151(11)60110-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
|
24
|
Vanhercke D, Claessens T, Van Ransbeeck P, Vandekerckhove H, De Bisschop F, Segers P, Verdonck P. P169 Poster Assessment of variables affecting late left ventricular flow propagation velocity (Vpa): an echocardiographic study. Eur J Cardiovasc Nurs 2011. [DOI: 10.1016/s1474-51511160110-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Affiliation(s)
| | - T. Claessens
- BioMech, University College Ghent, Ghent, Belgium
| | | | | | - F. De Bisschop
- Ghent University, Physics Laboratory - Faculty of Medicine & Health Sciences, Ghent, Belgium
| | - P. Segers
- Ghent University, Institute for Biomedical Technology (BioMMeda-IBiTech), Ghent, Belgium
| | - P. Verdonck
- Ghent University, Institute for Biomedical Technology (BioMMeda-IBiTech), Ghent, Belgium
| |
Collapse
|
25
|
Van Holsbeke C, De Backer J, Vos W, Verdonck P, Van Ransbeeck P, Claessens T, Braem M, Vanderveken O, De Backer W. Anatomical and functional changes in the upper airways of sleep apnea patients due to mandibular repositioning: A large scale study. J Biomech 2011; 44:442-9. [DOI: 10.1016/j.jbiomech.2010.09.026] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2010] [Revised: 09/20/2010] [Accepted: 09/27/2010] [Indexed: 11/27/2022]
|
26
|
Preston RS, Philp A, Claessens T, Gijezen L, Dydensborg AB, Dunlop EA, Harper KT, Brinkhuizen T, Menko FH, Davies DM, Land SC, Pause A, Baar K, van Steensel MAM, Tee AR. Absence of the Birt-Hogg-Dubé gene product is associated with increased hypoxia-inducible factor transcriptional activity and a loss of metabolic flexibility. Oncogene 2010; 30:1159-73. [PMID: 21057536 DOI: 10.1038/onc.2010.497] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Under conditions of reduced tissue oxygenation, hypoxia-inducible factor (HIF) controls many processes, including angiogenesis and cellular metabolism, and also influences cell proliferation and survival decisions. HIF is centrally involved in tumour growth in inherited diseases that give rise to renal cell carcinoma (RCC), such as Von Hippel-Lindau syndrome and tuberous sclerosis complex. In this study, we examined whether HIF is involved in tumour formation of RCC in Birt-Hogg-Dubé syndrome. For this, we analysed a Birt-Hogg-Dubé patient-derived renal tumour cell line (UOK257) that is devoid of the Birt-Hogg-Dubé protein (BHD) and observed high levels of HIF activity. Knockdown of BHD expression also caused a threefold activation of HIF, which was not as a consequence of more HIF1α or HIF2α protein. Transcription of HIF target genes VEGF, BNIP3 and CCND1 was also increased. We found nuclear localization of HIF1α and increased expression of VEGF, BNIP3 and GLUT1 in a chromophobe carcinoma from a Birt-Hogg-Dubé patient. Our data also reveal that UOK257 cells have high lactate dehydrogenase, pyruvate kinase and 3-hydroxyacyl-CoA dehydrogenase activity. We observed increased expression of pyruvate dehydrogenase kinase 1 (a HIF gene target), which in turn leads to increased phosphorylation and inhibition of pyruvate dehydrogenase. Together with increased protein levels of GLUT1, our data reveal that UOK257 cells favour glycolytic rather than lipid metabolism (a cancer phenomenon termed the 'Warburg effect'). UOK257 cells also possessed a higher expression level of the L-lactate influx monocarboxylate transporter 1 and consequently utilized L-lactate as a metabolic fuel. As a result of their higher dependency on glycolysis, we were able to selectively inhibit the growth of these UOK257 cells by treatment with 2-deoxyglucose. This work suggests that targeting glycolytic metabolism may be used therapeutically to treat Birt-Hogg-Dubé-associated renal lesions.
Collapse
Affiliation(s)
- R S Preston
- Institute of Medical Genetics, Cardiff University, Heath Park, Cardiff, Wales, UK
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
27
|
Annerel S, Degroote J, Claessens T, Vierendeels J. Evaluation of a new Implicit Coupling Algorithm for the Partitioned Fluid-Structure Interaction Simulation of Bileaflet Mechanical Heart Valves. ACTA ACUST UNITED AC 2010. [DOI: 10.1088/1757-899x/10/1/012124] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
|
28
|
Chirinos JA, Segers P, De Buyzere ML, Kronmal RA, Raja MW, De Bacquer D, Claessens T, Gillebert TC, St John-Sutton M, Rietzschel ER. Left ventricular mass: allometric scaling, normative values, effect of obesity, and prognostic performance. Hypertension 2010; 56:91-8. [PMID: 20458004 DOI: 10.1161/hypertensionaha.110.150250] [Citation(s) in RCA: 183] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
The need for left ventricular mass (LVM) normalization to body size is well recognized. Currently used allometric exponents to normalize LVM may not account for the confounding effect of sex. Because sex is a strong determinant of body size and LVM, we hypothesized that these are subject to potential bias. We analyzed data from 7528 subjects enrolled in the Asklepios Study (n=2524) and the Multiethnic Study of Atherosclerosis (limited access data set; n=5,004) to assess metric relationships between LVM and body size, generate normative data for indexed LVM, and compare the ability of normalization methods to predict cardiovascular events. The allometric exponent that adequately described the LVM-body height relationship was 1.7 in both studies and significantly different from both the unity and 2.7, whereas the LVM-body surface area relationship was approximately linear. LVM/height(2.7) consistently demonstrated important residual relationships with body height and systematically misclassified subjects regarding the presence of LVH. LVH defined by LVM/height(1.7) was more sensitive than LVM/body surface area to identify obesity-related LVH and was most consistently associated with cardiovascular events and all-cause death. In contrast to current assumptions, LVM/height(2.7) is not an adequate method to normalize LVM for body size. We provide more appropriate normalization methods, normative data by 2D echocardiography and gradient-echo cardiac MRI, and cutoffs for defining LVH, along with prognostic validation data.
Collapse
Affiliation(s)
- Julio A Chirinos
- University of Pennsylvania/Philadelphia Veterans' Affairs Medical Center, Philadelphia, Pa, USA.
| | | | | | | | | | | | | | | | | | | |
Collapse
|
29
|
Claessens T, Verwilst P, Missant C, Claus P, Verdonck P, Wouters P, Segers P. In vitro, in vivo and numerical assessment of the working principle of the truCCOMS™ continuous cardiac output catheter system. Med Eng Phys 2009; 31:1299-306. [DOI: 10.1016/j.medengphy.2009.08.010] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2008] [Revised: 08/17/2009] [Accepted: 08/22/2009] [Indexed: 11/30/2022]
|
30
|
Van Der Smissen B, Claessens T, Verdonck P, Van Ransbeeck P, Segers P. Design of an Artificial Left Ventricular Muscle: An Innovative Way to Actuate Blood Pumps? Artif Organs 2009; 33:464-8. [DOI: 10.1111/j.1525-1594.2009.00750.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
|
31
|
De Melis M, Morbiducci U, Rietzschel ER, De Buyzere M, Qasem A, Van Bortel L, Claessens T, Montevecchi FM, Avolio A, Segers P. Blood pressure waveform analysis by means of wavelet transform. Med Biol Eng Comput 2008; 47:165-73. [PMID: 18825426 DOI: 10.1007/s11517-008-0397-9] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2008] [Accepted: 09/11/2008] [Indexed: 11/30/2022]
Abstract
The assessment of cardiovascular function by means of arterial pulse wave analysis (PWA) is well established in clinical practice. PWA is applied to study risk stratification in hypertension, with emphasis on the measurement of the augmentation index as a measure of aortic pressure wave reflections. Despite the fact that the prognostic power of PWA, in its current form, still remains to be demonstrated in the general population, there is general agreement that analysis and interpretation of the waveform might provide a deeper insight in cardiovascular pathophysiology. We propose here the use of wavelet analysis (WA) as a tool to quantify arterial pressure waveform features, with a twofold aim. First, we discuss a specific use of wavelet transform in the study of pressure waveform morphology, and its potential role in ascertaining the dynamics of temporal properties of arterial pressure waveforms. Second, we apply WA to evaluate a database of carotid artery pressure waveforms of healthy middle-aged women and men. Wavelet analysis has the potential to extract specific features (wavelet details), related to wave reflection and aortic valve closure, from a measured waveform. Analysis showed that the fifth detail, one of the waveform features extracted applying the wavelet decomposition, appeared to be the most appropriate for the analysis of carotid artery pressure waveforms. What remains to be assessed is how the information embedded in this detail can be further processed and transformed into quantitative data, and how it can be rendered useful for automated waveform classification and arterial function parameters with potential clinical applications.
Collapse
Affiliation(s)
- Mirko De Melis
- Cardiovascular Mechanics and Biofluid Dynamics, IBiTech, Ghent University, Ghent, Belgium.
| | | | | | | | | | | | | | | | | | | |
Collapse
|
32
|
Kaminsky R, Kallweit S, Weber HJ, Claessens T, Jozwik K, Verdonck P. Flow Visualization Through Two Types of Aortic Prosthetic Heart Valves Using Stereoscopic High-speed Particle Image Velocimetry. Artif Organs 2007; 31:869-79. [DOI: 10.1111/j.1525-1594.2007.00471.x] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
|
33
|
Van Der Smissen B, Claessens T, Meyns G, Van Ransbeeck P, Segers P, Verdonck PR. A novel hydraulic thick-walled phantom for the assessment of left ventricular function. Comput Methods Biomech Biomed Engin 2007. [DOI: 10.1080/10255840701478836] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
|
34
|
Vanhercke D, Claessens T, Vandekerckhove H, Van Tricht I, Segers P, Verdonck P. Assessment of the Tilting Properties of the Human Mitral Valve during Three Main Phases of the Heart Cycle: An Echocardiographic Study. Echocardiography 2006; 23:265-70. [PMID: 16640702 DOI: 10.1111/j.1540-8175.2006.00209.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
RATIONALE AND OBJECTIVES In experimental models of the left heart, the mitral valve (MV) is commonly implanted perpendicular to a central axis of the apex/MV. To adapt this to a more correct anatomical model, as well as for further studies of the left ventricle, we created a database of implantation angles of the MV and annulus during three main phases of the heart cycle, based on standard cardiac ultrasound measurements. MATERIALS AND METHODS Twenty-eight patients were studied with the standard cardiac ultrasound equipment. From the apical echo window, an anteroposterior (AP) plane and a perpendicular commisure-commisure (CC) plane were generated during three critical moments in the heart cycle: systole (S); diastole early filling (E); and diastole late filling (A). In both planes, the angles between the annular plane and each mitral leaflet, as well as the angle between a theoretical longitudinal axis through the apex and center of the MV orifice and the mitral annulus plane, were measured with a custom-made application of Matlab R14. RESULTS We observed an inclination of the angle mitral annulus/central left ventricle axis, with its lowest point in the direction of the aortic valve (AP plane) of 85 degrees+/-7 degrees in systole (S), 88 degrees+/-8 degrees in early diastole (E), and 88 degrees+/-7 degrees in late diastole (A). In the CC plane, we observed an almost horizontal implantation of 91 degrees+/-5 degrees in systole (S), 91 degrees+/-8 degrees in early diastole (E), and 91 degrees+/-7 degrees in late diastole (A).
Collapse
Affiliation(s)
- Daniel Vanhercke
- Department of Cardiovascular Diseases, General Hospital St. Lucas, and Hydraulics Laboratory, Cardiovascular Mechanics and Biofluid Dynamics Research Unit, Ghent University, Belgium.
| | | | | | | | | | | |
Collapse
|
35
|
Segers P, Rietzschel E, Claessens T, De Buyzere M, De Bacquer D, De Backer G, Gillebert T, Verdonck P. Non-invasive assessment of ventriculo-arterial coupling in a middle-aged population of healthy men and women. J Biomech 2006. [DOI: 10.1016/s0021-9290(06)84110-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
|
36
|
Ama' R, Segers P, Roosens C, Claessens T, Verdonck P, Poelaert J. Impact of Volume Loading on Systolic Mitral Annular Velocity (Sm) by Tissue Doppler Imaging. Anesth Analg 2005; 100:901. [PMID: 15728099 DOI: 10.1213/01.ane.0000154228.09074.43] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Affiliation(s)
- Ruggero Ama'
- *Department of ICU; Ghent University Hospital and International Research Center †Hydraulics Laboratory; Institute Biomedical Technology; Ghent University; Ghent, Belgium;
| | | | | | | | | | | |
Collapse
|
37
|
De Bondt P, Claessens T, Rys B, De Winter O, Vandenberghe S, Segers P, Verdonck P, Dierckx RA. Accuracy of 4 different algorithms for the analysis of tomographic radionuclide ventriculography using a physical, dynamic 4-chamber cardiac phantom. J Nucl Med 2005; 46:165-71. [PMID: 15632048] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/01/2023] Open
Abstract
UNLABELLED Various automatic algorithms are now being developed to calculate left ventricular (LV) and right ventricular (RV) ejection fraction from tomographic radionuclide ventriculography. We tested the performance of 4 of these algorithms in estimating LV and RV volume and ejection fraction using a dynamic 4-chamber cardiac phantom. METHODS We developed a realistic physical, dynamic 4-chamber cardiac phantom and acquired 25 tomographic radionuclide ventriculography images within a wide range of end-diastolic volumes, end-systolic volumes, and stroke volumes. We assessed the ability of 4 algorithms (QBS, QUBE, 4D-MSPECT, and BP-SPECT) to calculate LV and RV volume and ejection fraction. RESULTS For the left ventricle, the correlations between reference and estimated volumes (0.93, 0.93, 0.96, and 0.93 for QBS, QUBE, 4D-MSPECT, and BP-SPECT, respectively; all with P < 0.001) and ejection fractions (0.90, 0.93, 0.88, and 0.92, respectively; all with P < 0.001) were good, although all algorithms underestimated the volumes (mean difference [+/-2 SDs] from Bland-Altman analysis: -39.83 +/- 43.12 mL, -33.39 +/- 38.12 mL, -33.29 +/- 40.70 mL, and -16.61 +/- 39.64 mL, respectively). The underestimation by QBS, QUBE, and 4D-MSPECT was greater for higher volumes. QBS, QUBE, and BP-SPECT could also be tested for the right ventricle. Correlations were good for the volumes (0.93, 0.95, and 0.97 for QBS, QUBE, and BP-SPECT, respectively; all with P < 0.001). In terms of absolute volume estimation, the mean differences (+/-2 SDs) from Bland-Altman analysis were -41.28 +/- 43.66 mL, 11.13 +/- 49.26 mL, and -13.11 +/- 28.20 mL, respectively. Calculation of RV ejection fraction correlated well with true values (0.84, 0.92, and 0.94, respectively; all with P < 0.001), although an overestimation was seen for higher ejection fractions. CONCLUSION Calculation of LV and RV ejection fraction based on tomographic radionuclide ventriculography was accurate for all tested algorithms. All algorithms underestimated LV volume; estimation of RV volume seemed more difficult, with different results for each algorithm. The more irregular shape and inclusion of a relatively hypokinetic RV outflow tract in the right ventricle seemed to cause the greater difficulty with delineation of the right ventricle, compared with the left ventricle.
Collapse
MESH Headings
- Algorithms
- Cardiac Volume
- Heart Ventricles/diagnostic imaging
- Humans
- Image Interpretation, Computer-Assisted/instrumentation
- Image Interpretation, Computer-Assisted/methods
- Imaging, Three-Dimensional/instrumentation
- Imaging, Three-Dimensional/methods
- Phantoms, Imaging
- Radionuclide Ventriculography/instrumentation
- Radionuclide Ventriculography/methods
- Reproducibility of Results
- Sensitivity and Specificity
- Software Validation
- Stroke Volume
- Tomography, Emission-Computed, Single-Photon/instrumentation
- Tomography, Emission-Computed, Single-Photon/methods
- Ventricular Function
- Ventricular Function, Left/physiology
- Ventricular Function, Right/physiology
Collapse
Affiliation(s)
- Pieter De Bondt
- Division of Nuclear Medicine, P7, Ghent University Hospital, 9000 Ghent, Belgium.
| | | | | | | | | | | | | | | |
Collapse
|
38
|
Amà R, Claessens T, Roosens C, Segers P, Verdonck P, Poelaert J. A comparative study of preload-adjusted maximal and peak power: assessment of ventricular performance in clinical practice. Anaesthesia 2004; 60:35-40. [PMID: 15601270 DOI: 10.1111/j.1365-2044.2004.03974.x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
This study was performed to determine whether preload-adjusted peak power can act as a surrogate for preload-adjusted maximal power in the assessment of left ventricular performance in the clinical setting. Ninety-nine consecutive patients who had undergone elective coronary artery bypass grafting were studied. Fifty-five of these patients were divided into four study groups. Afterload was changed with phenylephrine (n = 12) or glyceryl trinitrate (n = 13), preload was increased with intravenous colloid (n = 18), and contractility was increased with dobutamine (n = 12). There was excellent correlation between the two indices (r = 0.99, y = 1.0168x + 0.0769; p < 0.0001). Manipulation of neither preload nor afterload affected the indices. Both indices increased significantly during dobutamine infusion (p = 0.002). In conclusion, preload-adjusted peak power can be used as a substitute for preload-adjusted maximal power in the determination of ventricular performance in clinical practice.
Collapse
Affiliation(s)
- R Amà
- Institute Biomedical Technology, Ghent University, Ghent, Belgium
| | | | | | | | | | | |
Collapse
|
39
|
Langeland S, D'hooge J, Claessens T, Claus P, Verdonck P, Suetens P, Sutherland GR, Bijnens B. RF-based two-dimensional cardiac strain estimation: a validation study in a tissue-mimicking phantom. IEEE Trans Ultrason Ferroelectr Freq Control 2004; 51:1537-1546. [PMID: 15600099 DOI: 10.1109/tuffc.2004.1367495] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Strain and strain rate imaging have been shown to be useful techniques for the assessment of cardiac function. However, one of the major problems of these techniques is their angle dependency. In order to overcome this problem, a new method for estimating the strain (rate) tensor had previously been proposed by our lab. The aim of this study was to validate this methodology in a phantom setup. A tubular thick-walled tissue-mimicking phantom was fixed in a water tank. Varying the intraluminal pressure resulted in a cyclic radial deformation. The 2D strain was calculated from the 2D velocity estimates, obtained from 2D radio frequency (RF) tracking using a 1D kernel. Additionally, ultrasonic microcrystals were implanted on the outer and inner walls of the tube in order to give an independent measurement of the instantaneous wall thickness. The two methods were compared by means of linear regression, the correlation coefficient, and Bland-Altman statistics. As expected, the strain estimates dominated by the azimuth velocity component were less accurate than the ones dominated by the axial velocity component. Correlation coefficients were found to be r = 0.78 for the former estimates and r = 0.83 was found for the latter. Given that the overall shape and timing of the 2D deformation were very accurate (r = 0.95 and r = 0.84), these results were within acceptable limits for clinical applications. The 2D RF-tracking using a 1D kernel thus allows for 2D, and therefore angle-independent, strain estimation.
Collapse
|
40
|
Sprong H, Degroote S, Claessens T, van Drunen J, Oorschot V, Westerink BH, Hirabayashi Y, Klumperman J, van der Sluijs P, van Meer G. Glycosphingolipids are required for sorting melanosomal proteins in the Golgi complex. J Cell Biol 2001; 155:369-80. [PMID: 11673476 PMCID: PMC2150844 DOI: 10.1083/jcb.200106104] [Citation(s) in RCA: 101] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Although glycosphingolipids are ubiquitously expressed and essential for multicellular organisms, surprisingly little is known about their intracellular functions. To explore the role of glycosphingolipids in membrane transport, we used the glycosphingolipid-deficient GM95 mouse melanoma cell line. We found that GM95 cells do not make melanin pigment because tyrosinase, the first and rate-limiting enzyme in melanin synthesis, was not targeted to melanosomes but accumulated in the Golgi complex. However, tyrosinase-related protein 1 still reached melanosomal structures via the plasma membrane instead of the direct pathway from the Golgi. Delivery of lysosomal enzymes from the Golgi complex to endosomes was normal, suggesting that this pathway is not affected by the absence of glycosphingolipids. Loss of pigmentation was due to tyrosinase mislocalization, since transfection of tyrosinase with an extended transmembrane domain, which bypassed the transport block, restored pigmentation. Transfection of ceramide glucosyltransferase or addition of glucosylsphingosine restored tyrosinase transport and pigmentation. We conclude that protein transport from Golgi to melanosomes via the direct pathway requires glycosphingolipids.
Collapse
Affiliation(s)
- H Sprong
- Department of Cell Biology and Histology, Academic Medical Center, University of Amsterdam, 1100 DE, Amsterdam, Netherlands
| | | | | | | | | | | | | | | | | | | |
Collapse
|